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1 2 3  #include &amp;lt;pthread.h&amp;gt; #include &amp;lt;time.h&amp;gt; int pthread_mutex_timedlock(pthread_mutex_t * restrict mutex, const struct timespec *restrict tsptr);   愿意等待timespec描述的时间，达到时间返回错误码ETIMEOUT 一个例子
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时间锁


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#include &lt;pthread.h&gt;
#include &lt;time.h&gt;
int pthread_mutex_timedlock(pthread_mutex_t * restrict mutex, const struct timespec *restrict tsptr);


愿意等待timespec描述的时间，达到时间返回错误码ETIMEOUT
一个例子" />
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时间锁


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#include &lt;pthread.h&gt;
#include &lt;time.h&gt;
int pthread_mutex_timedlock(pthread_mutex_t * restrict mutex, const struct timespec *restrict tsptr);


愿意等待timespec描述的时间，达到时间返回错误码ETIMEOUT
一个例子">
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时间锁


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#include &lt;pthread.h&gt;
#include &lt;time.h&gt;
int pthread_mutex_timedlock(pthread_mutex_t * restrict mutex, const struct timespec *restrict tsptr);


愿意等待timespec描述的时间，达到时间返回错误码ETIMEOUT
一个例子"/>

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      <h1 class="post-title">线程同步2</h1>

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        <span class="post-time"> 2019-12-09 </span>
        
        
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      <h1 id="线程同步2">线程同步2</h1>
<p>时间锁</p>
<div class="highlight"><div class="chroma">
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<td class="lntd">
<pre class="chroma"><code class="language-fallback" data-lang="fallback">#include &lt;pthread.h&gt;
#include &lt;time.h&gt;
int pthread_mutex_timedlock(pthread_mutex_t * restrict mutex, const struct timespec *restrict tsptr);
</code></pre></td></tr></table>
</div>
</div><p>愿意等待timespec描述的时间，达到时间返回错误码ETIMEOUT
一个例子</p>
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<td class="lntd">
<pre class="chroma"><code class="language-c" data-lang="c"><span class="c1">// APUE example11-13                                       
</span><span class="c1">// pthread_mutex_timedlock                                 
</span><span class="c1">// lcl 20190325                                            
</span><span class="c1">//                                                         
</span><span class="c1"></span><span class="cp">#include</span> <span class="cpf">&#34;../myapue.h&#34;                                     </span><span class="cp">
</span><span class="cp">#include</span> <span class="cpf">&lt;pthread.h&gt;                                       </span><span class="cp">
</span><span class="cp">#include</span> <span class="cpf">&lt;time.h&gt;                                          </span><span class="cp">
</span><span class="cp"></span>
<span class="kt">int</span> <span class="nf">main</span> <span class="p">(</span><span class="kt">void</span><span class="p">)</span>                                            
<span class="p">{</span>                                                          
    <span class="kt">int</span> <span class="n">err</span><span class="p">;</span>                                               
    <span class="k">struct</span> <span class="n">timespec</span> <span class="n">tout</span><span class="p">;</span>                                  
    <span class="k">struct</span> <span class="n">tm</span> <span class="o">*</span><span class="n">tmp</span><span class="p">;</span>                                        
    <span class="kt">char</span> <span class="n">buf</span><span class="p">[</span><span class="mi">64</span><span class="p">];</span>                                          
    <span class="n">pthread_mutex_t</span> <span class="n">lock</span> <span class="o">=</span> <span class="n">PTHREAD_MUTEX_INITIALIZER</span><span class="p">;</span>      

    <span class="n">pthread_mutex_lock</span><span class="p">(</span><span class="o">&amp;</span><span class="n">lock</span><span class="p">);</span>                             
    <span class="n">printf</span><span class="p">(</span><span class="s">&#34;the mutex now is locked</span><span class="se">\n</span><span class="s">&#34;</span><span class="p">);</span>                   
    <span class="n">clock_gettime</span><span class="p">(</span><span class="n">CLOCK_REALTIME</span><span class="p">,</span> <span class="o">&amp;</span><span class="n">tout</span><span class="p">);</span>                  
    <span class="n">tmp</span> <span class="o">=</span> <span class="n">localtime</span><span class="p">(</span><span class="o">&amp;</span><span class="n">tout</span><span class="p">.</span><span class="n">tv_sec</span><span class="p">);</span>                         
    <span class="n">strftime</span><span class="p">(</span><span class="n">buf</span><span class="p">,</span> <span class="k">sizeof</span><span class="p">(</span><span class="n">buf</span><span class="p">),</span> <span class="s">&#34;%r&#34;</span><span class="p">,</span> <span class="n">tmp</span><span class="p">);</span>                 
    <span class="n">printf</span><span class="p">(</span><span class="s">&#34;current time is %s</span><span class="se">\n</span><span class="s">&#34;</span><span class="p">,</span><span class="n">buf</span><span class="p">);</span>                    

    <span class="n">tout</span><span class="p">.</span><span class="n">tv_sec</span> <span class="o">+=</span> <span class="mi">10</span><span class="p">;</span>                                     
    <span class="n">err</span> <span class="o">=</span> <span class="n">pthread_mutex_timedlock</span><span class="p">(</span><span class="o">&amp;</span><span class="n">lock</span><span class="p">,</span><span class="o">&amp;</span><span class="n">tout</span><span class="p">);</span>            

    <span class="n">clock_gettime</span><span class="p">(</span><span class="n">CLOCK_REALTIME</span><span class="p">,</span> <span class="o">&amp;</span><span class="n">tout</span><span class="p">);</span>                  
    <span class="n">tmp</span> <span class="o">=</span> <span class="n">localtime</span><span class="p">(</span><span class="o">&amp;</span><span class="n">tout</span><span class="p">.</span><span class="n">tv_sec</span><span class="p">);</span>                         
    <span class="n">strftime</span><span class="p">(</span><span class="n">buf</span><span class="p">,</span><span class="k">sizeof</span><span class="p">(</span><span class="n">buf</span><span class="p">),</span> <span class="s">&#34;%r&#34;</span><span class="p">,</span> <span class="n">tmp</span><span class="p">);</span>                  
    <span class="n">printf</span><span class="p">(</span><span class="s">&#34;the time is now %s</span><span class="se">\n</span><span class="s">&#34;</span><span class="p">,</span><span class="n">buf</span><span class="p">);</span>                    

    <span class="k">if</span><span class="p">(</span><span class="n">err</span> <span class="o">==</span> <span class="mi">0</span><span class="p">)</span>                                           
      <span class="n">printf</span><span class="p">(</span><span class="s">&#34;mutex locked again!</span><span class="se">\n</span><span class="s">&#34;</span><span class="p">);</span>                     
    <span class="k">else</span>                                                   
      <span class="n">printf</span><span class="p">(</span><span class="s">&#34;can&#39;t lock mutex again:%s</span><span class="se">\n</span><span class="s">&#34;</span><span class="p">,</span><span class="n">strerror</span><span class="p">(</span><span class="n">err</span><span class="p">));</span>
    <span class="n">exit</span><span class="p">(</span><span class="mi">0</span><span class="p">);</span>                                               
<span class="p">}</span>                                                          


</code></pre></td></tr></table>
</div>
</div><p>运行结果：</p>
<div class="highlight"><div class="chroma">
<table class="lntable"><tr><td class="lntd">
<pre class="chroma"><code><span class="lnt">1
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<td class="lntd">
<pre class="chroma"><code class="language-fallback" data-lang="fallback">the mutex now is locked
current time is 01:08:51 PM
the time is now 01:09:01 PM
can&#39;t lock mutex again:Connection timed out
</code></pre></td></tr></table>
</div>
</div><p>读写锁，三种状态读加锁、写加锁和不加锁</p>
<div class="highlight"><div class="chroma">
<table class="lntable"><tr><td class="lntd">
<pre class="chroma"><code><span class="lnt">1
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<td class="lntd">
<pre class="chroma"><code class="language-c" data-lang="c"><span class="cp">#include</span> <span class="cpf">&lt;pthread.h&gt;</span><span class="cp">
</span><span class="cp"></span><span class="kt">int</span> <span class="nf">pthread_rwlock_init</span><span class="p">(</span><span class="n">pthread_rwlock_t</span> <span class="o">*</span><span class="kr">restrict</span> <span class="n">rwlock</span><span class="p">,</span>
                                      <span class="k">const</span> <span class="n">pthread_rwlockattr_t</span> <span class="o">*</span><span class="kr">restrict</span> <span class="n">attr</span><span class="p">);</span>
<span class="kt">int</span> <span class="nf">pthread_rwlock_destory</span><span class="p">(</span><span class="n">pthread_rwlock_t</span> <span class="o">*</span><span class="n">rwlock</span><span class="p">);</span>

<span class="kt">int</span> <span class="n">pthread_rwlock_rdlock</span><span class="p">(</span><span class="n">pthread_rwlock_t</span> <span class="o">*</span><span class="n">rwlock</span><span class="p">)</span>
<span class="kt">int</span> <span class="n">pthread_rwlock_wrlock</span><span class="p">(</span><span class="n">pthread_rwlock_t</span> <span class="o">*</span><span class="n">rwlock</span><span class="p">)</span>
<span class="kt">int</span> <span class="n">pthread_rwlock_unlock</span><span class="p">(</span><span class="n">pthread_rwlock_t</span> <span class="o">*</span><span class="n">rwlock</span><span class="p">)</span>
</code></pre></td></tr></table>
</div>
</div><p>如上，函数名可以很好的反映函数的功能。</p>
<ul>
<li>写锁阻塞其他加锁</li>
<li>读锁阻塞写锁但不阻塞读锁</li>
<li>写锁在阻塞时，不再响应其他读锁请求。</li>
</ul>
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